Formulations for the prevention or the treatment of diseases affecting mucosae or skin, or for pregnancy prevention, and an applicator for the delivery of topical formulations into mucosal cavities

ABSTRACT

This invention relates to formulations for the prevention of infection and/or abnormal conditions of mucosae and/or skin caused by any pathogen and/or any disease, and more particularly for the prevention of sexually transmitted infections specially HIV and HSV. This invention also relates to formulations for the treatment of infection and/or abnormal conditions of skin and/or mucosae and more particularly for the treatment of herpetic lesions. The formulations could be used as a prophylactic agent to prevent accidental infection of health care workers. The formulations could be used for the healing and/or treatment of burn wounds and prevention of further infection. This invention also relates to the development of a unique vaginal/ano-rectal applicator for the uniform delivery of any topical formulations to treat and/or prevent any infection and/or abnormal conditions of mucosa cavity caused by any pathogen and/or disease.

This application is a continuation of PCT/CA99/00359 file Apr. 1, 1999.

FIELD OF THE INVENTION

This invention relates to formulations comprising film-formingcomponents and any active ingredient, particularly to topicalformulations. More particularly, this invention relates to topicalformulations to prevent or to treat diseases associated with ortransmitted through mucosae or skin, caused by any causative agent,particularly a pathogen. This invention also relates to an applicatorfor the uniform delivery of topical formulations to prevent or to treatany disease associated with or transmitted through mucosal cavity, or toprevent invasion by an external agent such as sperm or microbe.

BACKGROUND OF THE INVENTION

The spread of sexually transmitted diseases (STDs) caused by humanimmunodeficiency virus (HIV), herpes and other pathogens is going at abewildering rhythm. The global incidence, morbidity, and mortality ofSTDs are very significant. Worldwide, it is estimated that over 900million individuals are infected with sexually transmitted pathogens.Each year more than 12 million people in the United States are newlyinfected with a pathogen responsible for STDs. Herpes simplex virustype-1 (HSV-1) and type-2 (HSV-2), are the most common causes of genitalulceration in developed countries. Genital herpes infection is lifelongand may result in painful and recurrent genital lesions, systemiccomplications, psychosocial morbidity and also serious neonatal diseasefollowing intrapartum transmission of HSV. The genital transmission ofthis pathogen is usually due to asymptomatic viral shedding by peoplewho are unaware that they are infected. HSV-2 is now detectable in 1 outof 5 americans 12 years of age or older. In addition, it is estimatedthat over one-third of the world's population has recurrent HSVinfections and has therefore the capability to transmit the virus duringepisodes of productive infection. Neisseria gonorrheae and Chlamydiatrachomatis are recognized as two of the most prevalent sexuallytransmitted bacterial infections. Worldwide, there is an estimatedannual incidence of 25 million cases of gonorrhea and 50 million casesof chlamydia. On the other hand, recent epidemiologic data indicate thatthe number of individuals infected with HIV is growing dramaticallythroughout the world. According to United Nations officials,epidemiologic data estimates suggest that as many as 16,000 individualsbecome infected with HIV every day during 1997. Recent statistics (as ofend 1997) from the World Health Organization (WHO) indicated that thereare about 31 million people infected with HIV worldwide and this numberis projected to reach 40 millions by year 2000.

Globally, heterosexual transmissions may account for 85-90% of HIVinfection. As there is no vaccine against HIV, preventive measures arethe only tools that can presently reduce the transmission of thisretrovirus. The consistent and careful use of condoms represents aneffective barrier against the sexual transmission of HIV and othersexually transmitted pathogens, but they should be used in all riskysexual intercourses to significantly reduce the probability of acquiringinfection. In Africa, the most intensive prevention programs were onlyable to increase condom use to approximately 70% of all sexualintercourses in female prostitutes. Consequently, doubts arise about thepossibilities of condom promotion in controlling the AIDS epidemic inhigh risk groups. In situations where heterosexual transmission of HIVis important, preventive measures where women could prevent their riskof contracting STDs could be an additional tool to restrain theepidemic. Such a protective tool may also be used in male homosexualrelations as it could provide additional protection under the control ofthe receptive partner. Therefore, it is important to develop barriermethod that could be used as an alternative to condoms where the personcould protect themselves against infection without having to ask theirsexual partners. Preventive measures aimed at blocking the initialtransmission of pathogens that are the causative agents of AIDS, herpesand other STDs will lead, of course, to enormous benefits.

The development of safe topical microbicides is actually a very highpriority for the World Health Organization (WHO) and the NationalInstitutes of Health (NIH) in the field of HIV prevention. A topicalmicrobicide is often composed of an active ingredient and a vehicle.Active ingredients may act via a variety of mechanisms including: i)disrupting the organism cell membrane, envelope or capside lipid orprotein constituents (e.g. detergent-type spermicides/microbicides suchas nonoxynol-9), ii) blocking the receptor-ligand interactions essentialfor infectivity (e.g. microbial adhesion inhibitors such as sulfatedcompounds), iii) inhibiting the intracellular or extracellularreplication of the pathogen (e.g. antimicrobial drugs), iv) altering thevaginal environment and reducing susceptibility to infection (e.g.buffering agents and products that maintain normal vaginal flora andenvironment) or v) enhancing local immune responses (e.g. immuneresponse modifiers). The overall efficacy of a topical microbicideagainst the sexual transmission of pathogens causing STDs depends on theefficacy of the active ingredient to be delivered and its ability tocover the entire vaginal/cervix area for maximal efficacy againstpathogens. The capacity of these active agents to cover the entirevaginal cavity greatly depends of the type of vehicle used. Typicalformulations of vehicles include gels, creams, foams, suppositories,sponges and films.

Most currently available vaginal formulations use the spermicidenonoxynol-9, a nonionic surfactant, as a microbicide. In vitro,nonoxynol-9 inactivates enveloped viruses, such as HSV, HIV and othermicroorganisms including Chlamydia trachomatis, Neisseria gonorrhoeae.However, the potential efficacy of nonoxynol-9 against HIV is not yetclearly established and results of clinical trials are controversial. Arecent controlled trial conducted among 1292 HIV-negative femalesex-workers in Cameroon showed that the use of a vaginal film containing70 mg nonoxynol-9 did not reduce the rate of new HIV, gonorrhea orchlamydia infection (Roddy et al., 1998, N. Engl. J. Med., 339:504-510).The failure of nonoxynol-9 film in reducing the transmission ofinfectious agents could be attributed to the incomplete coverage of theentire vagina/cervix area with the drug delivery system for nonoxynol-9or to the occurrence of mucosal toxicity favoring infection ofmicroorganisms. Because of the dramatic increase in the number ofindividuals throughout the world who are infected with HIV, herpes, orother sexually transmitted pathogens, there is an urgent need to developactive products and/or appropriate delivery systems that can reduce thesexual transmission of these pathogens with minimal mucosal irritationand minimal effects on the vaginal flora and pH.

Sodium lauryl sulfate (SLS) is a sulfated surfactant that denaturesmembrane proteins of pathogens. It thus has a dual action as a detergentand as a chaotropic agent. With this notion, we have performedexperiments to evaluate the potential microbicidal effect of SLS on HSVand HIV. Our preliminary studies clearly demonstrated that SLS modifiesin vitro the infectivities of both viruses. More recently, Howett et al.have confirmed our findings that SLS is also a potent inactivator ofHSV-2, HIV-1 (Antimicrob. Agents Chemother. 43(2): 314-321, 1999). Inaddition, they have shown that SLS is effective against rabbit, bovineand human papillomaviruses (non-enveloped viruses) after brief treatmentwith low concentrations of this product. However, this reference doesnot teach the use of a vehicle to deliver this potential microbicide.The choice of vehicle is very important because it affects theconcentration of available drugs, the duration of drug availability andthe degree of mucosal coverage by the formulation which are key factorsfor offering protection against invading pathogens. Another interestingcategory of candidate microbicides is microbial adhesion inhibitors,such as sulfated compounds, which block the interaction between hostcell receptor and microbe. A known example of microbial adhesioninhibitors is dextran sulfate (DS), a polysulfated carbohydrate, whichhas been shown to inhibit in vitro the infectivities of HIV andherpesviruses.

We have recently developed a gel formulation that could be applied tothe vaginal, cervical or ano-rectal mucosae and which could be effectiveto prevent sexually transmitted pathogens. One paramount characteristicof this gel formulation is its thermoreversible property. The transitionfrom the liquid state at room temperature to the gel state at bodytemperature is of prime importance because when applied on roughbiological surfaces such as the vaginal or ano-rectal epithelia, the gelshould penetrate into the smallest irregularities forming a goodphysical barrier against infectious agents. The gel formulation has thefollowing key characteristics that both FDA and NIH consider important:i) it is colorless, odorless and non-staining, ii) it should cover thewhole vagina/cervix because it is applied in liquid state, iii) it iscompatible with male latex condom, iv) it resists to elution by aqueousflow, v) it has a pH similar to that of a healthy vagina (pH 4.0-4.5),vi) it maintains the desired Theological properties under extreme heatand cold conditions and vii) it does not affect, in vitro, the normalvaginal flora, especially Lactobacillus spp.

Our international publication (WO 97/42962) discloses the use offormulations comprising film-forming components capable of forming perse a physical barrier to pathogens. Thermoreversible gels such aspoloxamers arc particularly preferred for that use. The film-formingformulations may further comprise microbicides, spermicides or any otherdrug, which choice is guided by the pathogen, organism or the disease tobe inactivated or treated. The formulations are therefore efficient as aphysical, and optionally, as a chemical or pharmacological barrier aswell as usable as a sustained drug-release system at the locus ofadministration. These formulations are intended for use in theprevention of sexually transmitted diseases, as well as in the treatmentof infections, cancer, inflammation or any disease or state whichrequires a pharmacological treatment. In addition, this publicationteaches that the formulation decreases the toxicity of potentspermicides/microbicides such as nonoxynol-9. However, this publicationdoes not specifically teach the use of SLS as a chemical candidate ofchoice incorporated into the topical formulations.

HSV-1 and HSV-2 are neurotropic viruses which infect principally theneuroectodermal tissues including the skin, the peripheral nerves andthe central nervous system. Mucosal or skin surfaces are the usual sitesof primary infection. Recurrent labialis herpes and genital herpesrepresent the most common clinical manifestations associated with HSV-1and HSV-2 infections, respectively. Recurrences are spontaneous but areassociated with physical or emotional stress, fever, exposure toultraviolet light, tissue damage and immune suppression. Although it isa mild disease in immunocompetent individuals, HSV infections aretroublesome, especially for patients with frequent episodes. Patientscompromised by either immune therapy or underlying disease haveincreased risk to develop HSV infections. Renal and cardiac transplantrecipients demonstrated an increased severity of infection. In addition,the outbreak of AIDS has reinforced the severity of HSV clinical diseasein immunocompromised hosts.

The current available topical antiviral treatments have only a limitedefficacy particularly against symptomatic recurrent herpes. The limitedefficacy of these topical formulations on the development of herpeticmucocutaneous lesions may be due to the poor ability of the drugs topenetrate into the skin. The stratum corneum or horny layer constitutesthe barrier for the penetration of most substances into the skin. Thislayer consists of corneocytes embedded in a double-layered lipid matrixcomposed of cholesterol, free fatty acids and ceramides. Consequently,the use of skin penetration enhancers could represent a convenientstrategy to increase the penetration of topical drug formulations intothe skin.

SLS is a surfactant which possesses skin penetration enhancer propertyby increasing the fluidity of epidermal lipids. The skin penetrationenhancer property of SLS combined with its ability to modify viralinfectivity via its detergent and chaotropic properties could furtherincrease the efficacy of topical drug formulations. Furthermore, becauseof its chaotropic properties, SLS may have a broader spectrum ofactivity against sperm, bacteria, fungi and viruses than another simpledetergent.

Poloxamers are widely used in numerous pharmaceutical applications andtheir nontoxic properties make them suitable for sustained drug deliverysystems. Poloxamers represent suitable matrices for dermatologicalapplications. Indeed, when applied in liquid form, poloxamers allow abetter surface coverage by penetrating into the smallest irregularitiesof the mucosa and/or skin. In addition, the reticular array formed bythese poloxamers may act as a sustained drug release system prolongingdrug action.

SUMMARY OF THE INVENTION

In accordance with the present invention, it is a first object toprovide formulations which comprise a film-forming component which isapplied to the surface of mucosae or skin, preferably in the form ofgel, cream or ointment. The gel formulations are to be used for coatingdifferent types of mucosae such as vaginal, cervical, ano-rectal, eye,mouth, nose, or skin to prevent infection and/or abnormal conditions ofmucosae and/or skin. Furthermore, the gel formulations can be appliedtopically to the eye for the treatment and/or prevention of infection ofophthalmic conditions. Preferably, a thermoreversible gel is used, whichis applied in a liquid form, spreads on the surface and forms asemi-solid coating after it reaches the temperature of this bodysurface. More preferably, the thermoreversible gel is composed ofpoloxamer 407. Similar polymers such as poloxamines can also be used.The above formulations also comprise an agent capable of interferingwith the organism cell membrane, envelope or capside lipid or proteinconstituents in a target cell, tissue or microbe. The above combinationof the film-forming component and the above agent may provide forformulations with improved efficacy and reduced toxicity.

In a specific embodiment, the agent is capable of interfering with thebinding of a microbial outer protein to a host receptor. In a morespecific embodiment, the agent is a microbial adhesion inhibitor, or isa detergent or a chaotropic agent capable of disrupting the integrity ofsaid microbial outer protein. In an even a more specific embodiment, themicrobial adhesion inhibitor is dextran sulfate; the detergent isselected from the group consisting of sodium lauryl sulfate,benzalkonium chloride, lauroyl sarcosine, polyoxyethylene fatty acylderivatives and polyoxyethylene sorbitan fatty acyl ester derivatives;and the chaotropic agent is sodium lauryl sulfate or guanidine. In themost specific embodiment, the agent is SLS, the latter being a chemicalcandidate of choice because of its numerous properties as a detergentand a chaotropic agent and a putative microbial adhesion inhibitor. SLSalone is efficient against microbes. SLS efficacy is further improvedwhen incorporated into the present formulations. Therefore, it iscontemplated that SLS or any equivalent product can be used alone or incombination with the above film-forming component to prevent microbialinfection. SLS may be used alone or in combination with the aboveformulations at any suitable concentration, preferably at aconcentration of about 0.1-25% (w/v), and more preferably at aconcentration of about 1-15% (w/v). Poloxamer 407 concentration may beused at any suitable concentration, preferably at a concentration ofabout 5-50% (w/v) and more preferably at a concentration of about 15-35%(w/v) The physical properties of the final formulations largely dependson the drug to be incorporated in them, on the pH and solutes used inthe making of the formulations and on the viscosity sought for a givenpurpose. The above formulations could further comprise a drug which iseffective to prevent infection and/or abnormal conditions of the mucosaeor skin. Vaginal formulations constitute a physical and a chemicalbarrier due to its film-forming and microbial disrupting components. Itgoes along that, with an activity against infective agents, theseformulations may also be effective for preventing pregnancy. SLS willadvantageously replace nonoxynol-9 in the formulations. SLS having abroader spectrum of activity against, inter alia, sperm, enveloped andnon-enveloped viruses, it is a candidate of choice in the presentformulation. The gel could contain a drug which is effective to preventinfection and/or abnormal conditions of mucosae and/or skin. For thepurpose of the invention, the term “drug” is intended to cover anyantimicrobial, bactericidal, virucidal, chemotherapeutic,antiinflammatory, antineoplastic, immunomodulator or any other agent orcombination of them which is effective for the prevention of infectionof mucosae and/or skin. The term “drug” also refers to cytokines orantigens that could stimulate an immune response that would protectagainst infection. The drugs could be incorporated within drug carrierssuch as gels, liposomes, nanoparticles or cyclodextrins, whoseencapsulation result in an improved prevention of infection.

It is further an object of the present invention to provide a uniqueapplicator that can be used vaginally and/or ano-rectally to delivertopical formulations for treatment and/or prevention of infection and/orabnormal conditions of mucosae. The applicator can be designed indifferent ways to give the same required characteristics specified underdetailed description of the invention. Examples of some differentconcepts are also discussed under the detailed description which areintended to describe some of the general design possibilities of theapplicator, but are in no way intended to limit the scope thereof. It isimportant to mention that the final shape and appearance of theapplicator can differ from the examples given herein.

In other preferred embodiments, the present formulations are used totreat viral diseases and they further comprise as a drug an antiviralagent such as acyclovir or foscarnet, or any other antimicrobial agents,used alone or in combination, at any suitable concentration. In a mostpreferred embodiment, the formulation is composed of poloxamer 407 andcontains foscarnet at a concentration ranging from 0.5 to 5% (w/v). Inanother most preferred embodiment, the formulation is composed ofpoloxamer 407 and contains acyclovir at a concentration ranging from 0.5to 5% (w/v). In still another most preferred embodiment, the formulationis composed of poloxamer 407 and contains SLS at a concentration rangingfrom 1 to 10% and foscarnet or acyclovir at the above concentrations.

It is an object of the present invention to develop new topicalformulations to prevent infection of mucosae and/or skin, moreparticularly those sexually transmitted infections and even moreparticularly those caused by HIV and herpes. The microbicides or anyother drug can be entrapped into the gel formulations either as free orencapsulated into drug carriers such as liposomes, nanoparticles orcyclodextrins. Such microbicidal gels could prolong the localmicrobicidal activity, eliminate local irritation and reduce systemicside effects of incorporated active agents.

It is also an objective of the invention to develop, for vaginalapplications, a unique applicator which allows uniform distribution ofthe content to the entire vagina (delivery to sides) and cervix(delivery to front) for maximal protection against the sexualtransmission of pathogens. Therefore, we have designed a uniqueapplicator which allows about 360° distribution of its content into thevagina and far to the cervix which is a great improvement over existingconventional vaginal applicators which deliver contents only to front(cervix area only).

It is another object of the present invention to develop topicalformulations of drugs which could improve the efficacy of chemically orpharmacologically active agents against mucocutaneous infections andmore particularly those caused by HSV infections. The improved efficacyof drugs upon incorporation within suitable matrices and/or drugcarriers could reduce the dosing interval and consequently improve thequality of life of patients. It is also an objective of the presentinvention to develop topical formulations for the treatment and/orhealing of burn wounds as well as to prevent their potential infection.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS OF THE PRESENT INVENTION

This invention will be described hereinbelow by referring to specificembodiments and appended figures, which purpose is to illustrate theinvention rather than to limit its scope.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the infectivity of HSV-1 (strain F) to Vero cells followingpretreatment of the virus with different concentrations of SLS (Panel A)or DS (Panel B) for 1 h at 37° C. () or following the addition of SLSor DS to viruses without pretreatment (∘). Plaque forming units (PFU)are expressed as percentage of control. Results are mean±SD of 4independent experiments.

FIG. 2 shows the efficacy of different concentrations of SLS (Panel A)or DS (Panel B) against HSV-1 (strain F) in Vero cells. Plaque formingunits (PFU) are expressed as percentage of control. Results are mean±SDof 4 independent experiments.

FIG. 3 illustrates the effect of pretreating HIV-1 (strain NL4-3) with500 μM of SLS for 1 h at 37° C. on its infectivity to 1G5 cells. Valuesrepresent the mean±SD of 3 determinations.

FIG. 4 shows electron micrographs of Vero cells infected with HSV-1(strain F) pretreated for 1 h at 37° C. with 50 μM (Panel B), 75 μM(Panel C) and 100 μM (Panel D) of SLS. Cells infected with HSV-1 (strainF) in absence of SLS were used as control (Panel A). Magnification70,000×.

FIG. 5 shows quantification of glycoprotein D of HSV-1 (strain F)pretreated for 1 h at 37° C. with 12.5, 25, 50, 75 and 100 μM of SLS inVero cells. Cells infected with HSV-1 (strain F) in EMEM +2% FBS wereused as control. Values are expressed as a percentage of thehybridization signal intensity compared to control.

FIG. 6 shows the time evolution of survival of mice infectedintranasally with HSV-2 (strain 22) pretreated for 1 h at 37° C. with6.25 (), 25 (∘) and 100 (▾) μM of SLS. Mice infected with untreatedvirus were used as control (□). Results are expressed as mean of 8animals per group.

FIG. 7 shows the time evolution of the mean lesion score of miceinfected cutaneously with HSV-1 (strain F) pretreated for 1 h at 37° C.with different concentrations (6.25 (), 25 (∘) and 100 (▾) μM) of SLS(Panel A) or different concentrations (0.25 (), 1 (∘) and 10 (▾) nM) ofDS (Panel B). Mice infected with untreated virus were used as control(□). Results are expressed as mean of 6 animals per group.

FIG. 8 shows the time evolution of mean lesion score of mice infectedwith HSV-1 (strain F) following pretreatment of mice with the poloxamerformulation alone 5 min (∘) or 1 h (Δ) prior to infection or with thepoloxamer formulation containing 5% SLS also 5 min () or 1 h (▾) priorto infection. Infected untreated mice were used as control (□). Resultsare expressed as mean of 6 animals per group.

FIG. 9 shows the time evolution of mean lesion score (Panel A) andsurvival (Panel B) of mice infected intravaginally with HSV-2 (strain333) pretreated with the gel alone (▪, ▾, ) 5 min prior to infection.Infected untreated mice were used as control (□, Δ, ∘). Results are meanof 8 animals per group.

FIG. 10 shows: the time evolution of survival of mice infectedintravaginally with HSV-2 (strain 333) pretreated with 2.5% SLS (*) orgel+2.5% SLS () 5 min prior to infection. Infected untreated mice wereused as control (□). Results are expressed as mean of 8 animals pergroup.

FIG. 11 shows the time evolution of survival of mice infectedintravaginally with HSV-2 (strain 333) pretreated with gel+5%polyoxyethylene 40 stearate (), gel+5% guanidine (∘), gel+2.5% lauroylsarcosine (▾), gel+2.5% benzalkonium chloride (Δ) or gel+5% tween 80 (♦)5 min prior to infection. Infected untreated mice were used as control(□). Results are mean of 7 to 10 animals per group.

FIG. 12a is a perspective view illustrating a first embodiment of anapplicator according to an aspect of the present invention.

FIG. 12b is a side elevational view showing the dimensions in inches ofthe applicator of FIG. 12a.

FIG. 12c is an exploded view of the components of the applicator of FIG.12a.

FIG. 12d is a perspective view illustrating the details of the externalsurface of the proximal end of the internal wall of the applicator ofFIG. 12a.

FIG. 13a is a perspective view illustrating a second embodiment of anapplicator according to an aspect of the present invention.

FIG. 13b is a side elevational view illustrating the dimensions ininches of the applicator of FIG. 13a in both insertion position andactuated position.

FIG. 13c is an exploded view of the applicator of FIG. 13a.

FIG. 14a is a perspective view of a third embodiment of an applicatoraccording to an aspect of the present invention; the applicator beingshown in an insertion position.

FIG. 14b is a perspective view of the applicator of FIG. 14a shown in anactuated position.

FIG. 14c is a side elevational view illustrating the internal details ofthe applicator of FIG. 14a in the insertion position.

FIG. 14d is a side elevational view illustrating the internal details ofthe applicator of FIG. 14a in the actuated position.

FIG. 15a is a perspective view of a fourth embodiment of the applicatoraccording to an aspect of the present invention.

FIG. 15b is an exploded view of the applicator of FIG. 15a.

FIG. 15c is a side elevational view of the external wall of theapplicator of FIG. 15a where the dimensions are given in inches.

FIG. 15d is a side elevational view of the piston/reservoir of theapplicator of FIG. 15a where the dimensions are given in inches.

FIG. 15e is a sectional side elevational view of a portion of theapplicator of FIG. 15a illustrating the details of the arrangement ofthe piston/reservoir with regard to the internal and external walls ofthe body of the applicator.

FIG. 16 shows the time evolution of mean lesion score (Panel A) andsurvival (Panel B) of hairless mice infected cutaneously with HSV-1 andtreated topically with the poloxamer alone (▪), 0.5% foscarnet inaqueous solution (∘) or poloxamer containing 0.5% foscarnet ().Infected untreated mice were used as control (□). Treatment started 24 hafter infection and was repeated 3 times daily for 4 days. Values areexpressed as mean of 4 animals per group.

FIG. 17 shows the time evolution of the mean lesion score (Panel A) andsurvival (Panel B) of hairless mice infected cutaneously with HSV-1(strain F) and treated 24 h postinfection with a single application ofeither poloxamer containing 5% acyclovir () or Zovirax® ointment (∘).Infected untreated mice (□) were used as controls. Values are expressedas mean of 7 to 10 animals per group.

FIG. 18 shows the time evolution of the mean lesion score (Panel A) andsurvival (Panel B) of hairless mice infected cutaneously with HSV-1(strain F) and treated with the poloxarner alone (▪), poloxamercontaining 5% acyclovir (), or with Zovirax® ointment (∘). Infecteduntreated mice (□) were used as controls. Treatment started 5 days afterthe infection and was repeated 3 times daily for 4 days. Values areexpressed as mean of 7 to 10 animals per group.

FIG. 19 shows the distribution of foscarnet (Δ, ▾) and acyclovir (∘, )in skin tissues of uninfected (Panels A, C, E) and infected (Panels B,D, F) mice at 24 h after their topical application, either in phosphatebuffer (open symbols) or within the poloxamer (filled symbols). Panels Aand B show the distribution of foscarnet and acyclovir in the stratumcorneum strips. Panels C and D show the concentration of foscarnet andacyclovir in the epidermis whereas panels E and F show the concentrationof foscarnet and acyclovir in the dermis. Values are expressed as meanof 4 to 6 animals per group.

FIG. 20 shows the concentration of acyclovir in plasma of uninfected andinfected mice at 24 h after its topical application, either in phosphatebuffer (open bars) or in the poloxamer (filled bars). Values areexpressed as mean of 4 to 6 animals per group.

FIG. 21 shows the time evolution of mean lesion score (Panel A) andsurvival (Panel B) of hairless mice infected cutaneously with HSV-1(strain F) treated with the poloxamer alone (▪), poloxamer containing 3%foscarnet (∘), poloxamer containing 5% SLS () or poloxamer containing3% foscarnet+5% SLS (Δ). Infected untreated mice (□) were used ascontrols. Results are expressed as mean of 5 animals per group.

FIG. 22 shows the susceptibility of HSV-1 (strain F) to combinations ofdifferent concentrations of foscarnet and SLS in Vero cells. Values areexpressed as mean±SD of 3 determinations.

GEL FORMULATIONS

Poloxamer 407 is a block copolymer of polyoxyethylene andpolyoxypropylene in a 7:3 weight ratio with an average molecular weightof 12500. One important characteristic of this block copolymer is itsability to form a thermoreversible gel. The transition from the liquidstate at low temperature to the gel state at body temperature (the phasetransition temperature being dependent, in part, on the concentration ofthe gel, the ionic strength and the incorporated solute) allows a numberof interesting medical applications including topical applications. Suchcharacteristic is of prime importance because when applied topically inits fluid state to the mucosa, the gel formulation should allow betterpenetration into the irregularities of the skin and/or mucosae duringapplication and a longer persistence once the gel has reached bodytemperature. Because of the extremely low toxicity and irritancy of ourgel formulations, they represent an attractive approach for topical drugdelivery systems. Details for the preparation of the gel formulationsare provided hereafter. This invention covers gel formulations ofpoloxamer 407 of any suitable concentration, and more particularly thosebetween about 10 and 35% w/w. This invention also covers any otherfilm-forming component, gel, cream, ointment or thermoreversiblesubstance including other poloxamers, poloxamines or chemicals.

Drugs

Any antimicrobial, bactericidal, virucidal, chemotherapeutic,antiinflammatory, antineoplastic, immunomodulator or combination of themwhich is effective to prevent or treat infection and/or abnormalconditions of mucosae and/or skin caused by any pathogen and/or anydisease is under the scope of this invention. Any detergent which candisrupt the membrane of pathogens, any skin penetration enhancer thatincreases the penetration of drugs and/or drug carriers into the mucosaeand/or skin, any microbial adsorption inhibitor which preventspathogen's entry into a target cell, any cytokine or antigen that couldstimulate an immune response that would protect against pathogen'sinfection are also under the scope of this invention. This inventionalso covers any combination of topical formulations and/or drugs.

Examples Involving our: Gel Gormulations for Prevention of Infection

The following examples are intended to demonstrate the preparation ofgel formulations that could be efficient to prevent infection and/orabnormal conditions of mucosae and/or skin caused by any pathogen and/orany disease, but are in no way intended to limit the scope of thepresent invention.

Preparation of the Gel Formulations

The gel formulations are prepared by adding an appropriate volume ofdistilled water, buffer or any other suitable aqueous solution to thepoloxamer 407 to obtain the desired concentration. An appropriate amountof drugs are then added either to the powder or solution of poloxamer toreach the desired concentration. The pH of the gel formulation can beadjusted to meet the requirements of each target tissue to be coatedwith the present formulations. For instance, if a formulation is to beused to coat vaginal mucosa, an acidic solution with pH of about 4.0-4.5will be used. The percentage of polymer may be adjusted accordingly toobtain an adequate transition temperature from liquid to solid state.These adjustments are well within the knowledge and ability of theskilled artisan.

Even though the description of this invention is limited to specificcases, any film-forming component and/or drug and/or liposomes (or otherdrug carriers) or any combination of the above are considered aspotential candidates for the development of these topical presentationsand are under the scope of this invention. The formulations also includeany film-forming component and/or drug and/or liposomes (or other drugcarriers) or any combination of these products at any suitableconcentration.

In Vitro Infectivity of Herpes Viruses Pretreated with SLS or DS

The effect of pretreating different strains of herpes viruses with SLSor DS on their viral infectivities to susceptible cells has beenevaluated. In brief, cells were seeded in 24 well-plates (Costar,Montreal, QC, Canada). Prior to infection, the virus was eithersuspended in culture medium or phosphate buffered saline (PBS), orincubated with different concentrations of SLS in PBS for 1 h at 37° C.At confluency, cells were incubated with viral suspensions bycentrifuging the plates (750×g for 45 min at 20° C.) to allow virusadsorption. Virus was removed and cell sheets were then overlaid with0.5 ml of 0.6% agarose Seaplaque (Marine Colloids, Rockland, Mass.)prepared in appropriate culture medium. The plates were incubated for 2days at 37° C. Cells were then fixed with 10% formaldehyde in PBS for 20min, washed with deionized water and stained with 0.05% methylene blue.Viral infectivity was evaluated via the determination of Plaque FormingUnits (PFU).

Table 1 shows that pretreatment of various HSV-1 and HSV-2 strains withSLS for 1 h at 37° C. decreased, in a concentration-dependent manner,their infectivity on Vero cells. HSV-1 (strain F) infectivity wasreduced to 21% when viral particles were pretreated with 25 μM SLS. Theinfectivities of all HSV-2 strains were between 50 to 70% followingpreincubation with 25 μM SLS. A complete loss of the infectivity of allstrains tested were obtained following pretreatment of the viruses with50 μM SLS. Preincubation of Vero cells for 1 h at 37° C. with SLSconcentrations ranging from 6.25 to 100 μM prior to their infection withHSV-1 (strain F) did not result in a loss of infectivity of the virus(data not shown). These results suggest that SLS acts directly on thevirus and not on cells.

TABLE 1 Infectivity of various HSV-1 and HSV-2 strains pretreated withdifferent concentrations of SLS for 1 hour at 37° C. SLS concentrationPFU (% of control) for (μM) HSV-1 (F)^(a) HSV-2 (333)^(a) HSV-2 (22)^(a)HSV-2 (6)^(b) HSV-2 (15589)^(c) 6.25 101.1 ± 7.0 102.9 ± 23.5 128.0 ±18.5 105.3 ± 12.4 108.7 ± 22.2 12.5 79.2 ± 36.4 115.4 ± 17.0 103.4 ±14.9 82.1 ± 40.7 115.1 ± 17.5 25 21.2 ± 18.0 72.9 ± 9.1 63.8 ± 11.9 51.1± 30.1 59.0 ± 24.0 50 0 0 0 0 0 ^(a)wild-type strain^(b)acyclovir-resistant strain ^(c)foscarnet-resistant strain

FIG. 1 shows the effect of pretreatment of HSV-1 (strain F) withdifferent concentrations of SLS or DS on its infectivity to Vero cells.When SLS was immediately added to Vero cells following their infection,the loss of viral infectivity was less dramatic compared to thatobtained for virus pretreated for 1 h at 37° C. with the same SLSconcentrations. Following pretreatment, a loss of 50% of the viralinfectivity was observed at a concentration of 20 μM compared to 75 μMwhen the virus was not pretreated. Moreover, although a completeinhibition of viral infectivity was obtained following preincubationwith 50 μM SLS, the inhibition was not complete even at 100 μM withoutpretreatment. Similarly, pretreatment of the HSV-2 (strain 333) with SLSalso influenced the infectivity of this strain (data not shown). On theother hand, DS reduces the infectivity of the virus independent ofwhether the virus was pretreated with DS. In this case, a loss of 50% ofthe viral infectivity was observed at a concentration of about 1 nM.

The viability of Vero cells exposed for 1 h at 37° C. to SLS or DSconcentrations similar to those used in FIG. 1 and Table 1 was alsotested using an MTS test. No signs of cytotoxicity could be demonstratedin the range of concentrations used (data not shown).

FIG. 2 shows the efficacy of different concentrations of SLS (Panel A)or DS (Panel B) against HSV-1 (strain F) in Vero cells. In brief, cellswere infected with the virus for 2 h at 37° C. Afterwards, supernatantwas removed and cells were overlaid with 0.5 ml of EMEM+2% FBScontaining 0.6% agarose Seaplaque and SLS or DS at the desiredconcentration. Plates were then incubated for 2 days at 37° C. in a 5%CO₂ atmosphere. Cells were fixed with 10% formaldehyde in PBS for 20min, washed with deionized water and stained with 0.05% methylene blue.Viral infectivity was evaluated following the determination of PFU.Results show that both SLS and DS reduced in a concentration-dependentmanner the viral repication in a similar way with complete efficacy at100 μM and 20 nM for SLS and DS, respectively. Without being bound toany mechanism, the above results suggest that SLS may have a microbialadhesion inhibitor effect.

In Vitro Infectivity of HIV-1 Pretreated with SLS

The effect of pretreating HIV-1 (strain NL4-3) with SLS on itsinfectivity to 1G5 cells, a Jurkat E6-1 derivative that harbors twostably integrated constructs made up of the luciferase gene under thecontrol of the HIV-1_(SF2) LTR, has been also evaluated. In brief, priorto infection, the virus was incubated with either culture medium or 500μM SLS for 1 h at 37° C. Cells (1×10⁵ cells/well) were then incubatedwith HIV-1 strain NL4-3 (10 ng of p24) for 2 h at 37° C. under a 5% CO₂atmosphere. Afterwards, cells were washed, resuspended in 200 μl ofcomplete culture medium and transferred in a 96-well flat-bottomedtissue culture plate (Microtest III, Falcon; Becton Dickinson, LincolnPark, N.J.). After a 48 h incubation time at 37° C., cells were lysed,subject to a freeze-thaw cycle and luciferase activity was monitoredusing a microplate luminometer (MLX; Dynex Technologies, Chantilly,Va.). Results from this set of experiments clearly show thatpretreatment of HIV-1 (strain NL4-3) with 500 μM SLS for 1 h at 37° C.almost completely inhibited HIV-1 infectivity to 1G5 cells (FIG. 3).

Electron Microscopy of Vero Cells Infected with HSV-1 (Strain F)Pretreated with SLS

The appearance of HSV-1 (strain F) pretreated with varying SLSconcentrations (50, 75 and 100 μM) for 1 h at 37° C. has been evaluatedin Vero cells using electron microscopy. In brief, cells (80-90%confluent) were infected with the virus (approximately 70 PFU/ml in 14ml) for 48 h at 37° C. in a 5% CO₂ atmosphere. Cells were scrapped offfrom the dishes and resuspended in culture medium. Cells werecentrifuged (515×g for 10 min at 4° C.) and the supernatant was decantedand cells were resuspended in approximately 500 μl medium. Cells weretransferred in an eppendorf tube and centrifuged at (10,000×g for 5 minat 4° C.). The pellet was resuspended in approximately 200 μl of 20%bovine serum albumin (BSA). Few drops of 25% glutaraldehyde were addedto the mixture and samples were immediately put in an ice bath to allowBSA polymerization. The pellet was then cut in 1 mm³ samples which werethen fixed in 2% glutaraldehyde in PBS for 1 h, 1% OsO₄ in PBS for 1 hand then with 0.1% tannic acid in PBS for 30 min. Samples were rinsed 3times in PBS for 5 min between each step. Samples were stained with 2%uranyl acetate in 10% ethanol for 30 min. Samples were dehydrated andembedded in Epon following routine procedures. Sections (approximately75 nm thickness) were mounted on copper grid (200 mesh). Specimens werestained with uranyl acetate, counterstained with lead citrate andobserved with a JEOL 1010 electron microscope (JEOL Canada Inc.,St-Hubert, QC, Canada).

FIG. 4 (Panel A) shows the normal appearence of the virus in the nucleiof Vero cells. Viral particles were composed of a capsid, hexagonal inshape and, containing an electrondense DNA core. Complete viralparticles formed by a nucleocapsid surrounded by an envelope were alsofound in the cytoplasm of most cells. In Vero cells infected withviruses pretreated with 50 (Panel. B), 75 (Panel C) and 100 (Panel D) μMSLS, viral particles could be recovered in the nuclei but not in thecytoplasm of cells. No mature nucleocapsid could be observed in thenuclei but viral particles were constituted by capsids containing adiscrete accumulation of electron-dense material. The number of emptycapsids found in nuclei of cells infected with viruses pretreated withSLS decreased with the increased concentrations of drug used for thepretreatment,. In cells infected with viruses pretreated with 100 μMSLS, only a few cells with empty capsids in the nuclei could bedetected. Taken together, thes results could explain the loss ofinfectivity of herpes viruses in presence of SLS.

Quantification of HSV 2 Glycoprotein D Gene

The quantification of the glycoprotein D gene of HSV-1 (strain F)pretreated with SLS was also evaluated in Vero cells in order todetermine the presence of viral DNA in the infected cells. In brief,HSV-1 (strain F) was pretreated with varying SLS concentrations (12.5,25, 50, 75 and 100 μM) in EMEM+2% FBS for 1 h at 37° C. Vero cells(80-90% confluent) were infected with the virus (100 PFU/ml in 20 ml)for 48 h at 37° C. in a 5% CO₂ atmosphere. The culture medium wasremoved and cell sheet was washed twice with 1×HBSS. Cells were scrappedoff from the dishes and resuspended in EMEM+2% FBS. Total DNA wasextracted using a standard phenol/chloroform procedure. Quantitation oftotal DNA was achieved using the Burton procedure. The probe used forthis study corresponds to a part of glycoprotein D of HSV-2 (strain333), generated by PCR using the following primers:

P1 (5′-GCCACCATGGGGCGTTTGACC-3′) and

P2 (5′-AAACTCAGTTATCTAGTCCTCGGGGTC-3′)

and was [³²P]-labeled by random priming. Hybridization was performed at65° C. in 0.25 M Na₂HPO₄ (pH 6.8 with orthophosphoric acid) and 7% SDS.Washes were done in 40 mM Na₂HPO₄ (pH 6.8 with orthophosphoric acid) and1% SDS for 20 min at 65° C. followed by 20 min at 25° C.

FIG. 5 (Panel A) shows the quantification of the glycoprotein D gene ofHSV-1 (strain F) pretreated with varying concentrations of SLS in Verocells. Following a 48 h incubation, cells were collected and total DNAwas extracted. Panel A shows BglII-fragmented DNA aliquots (325 ng)applied to a 0.8% agarose gel, transferred to a nylon membrane, andhybridized with the glycoprotein D probe. Panel B shows the quantitativemeasurements of HSV-1 DNA levels obtained by scanning densitometry ofthe autoradiogram using an AlphaImager. No major modification in theexpression of the glycoprotein D gene of the virus could be observed incells infected with HSV-1 (strain F) pretreated with 12.5, 25 and 50 μMSLS compared to control. Quantitative measurements of HSV-1 DNA levelsobtained by scanning densitometry of the autoradiogram were similar(Panel B). However, when the virus was pretreated with higherconcentrations of SLS (75 and 100 μM), a marked reduction in theexpression of the glycoprotein D gene was observed with a reduction inthe DNA levels to 65.1% and 34.9% of control values, respectively. Thesedata suggest that SLS could interfere with the maturation of viralnucleocapsids either by reducing their rate of maturation or byinterfering with the encapsidation of DNA into the capsid shell.

In Vivo Infectivity of Herpes Viruses Pretreated with SLS (IntranasalModel)

The effect of pretreating HSV-2 (strain 22) with SLS on viralinfectivity has also been evaluated in a murine intranasal infectionmodel. In brief, female Balb/c mice (Charles River Breeding LaboratoriesInc., St-Constant, QC, Canada) 4 weeks-old were used throughout thisstudy. Prior to the infection, HSV-2 (strain 22) was incubated for 1 hat 37° C. with PBS or with different concentrations of SLS (6.25, 25 or100 μM) to reach a final viral inoculum of 2,000 PFU/20 μl. Mice wereslightly anesthetized using Aerrane® (Isoflurane, USP; Janssen, NorthYork, ON, Canada) and viral suspension (20 μl total volume) was appliedinto the external left nare of mice. Mice were then returned to theircages and survival was evaluated daily.

FIG. 6 shows that all mice infected with untreated virus died ofencephalitis between day 9 and day 11. In contrast, 67% of mice infectedwith the viral inoculum pretreated with 6.25 and 25 μM SLS survived theinfection. Of prime interest, all mice infected with a viral suspensionpretreated with 100 μM SLS survived the infection and did notdemonstrate any sign of illness.

In Vivo Infectivity of Herpes Viruses Pretreated with SLS or DS(Cutaneous Model)

The effect of pretreating HSV-1 (strain F) with SLS on viral infectivityhas also been evaluated in a murine cutaneous infection model. Femalehairless mice (SKH1; Charles River Breeding Laboratories Inc.,St-Constant, QC, Canada), 5-6 weeks old were used throughout this study.Prior to infection, HSV-1 (strain F) was incubated for 1 h at 37° C.with PBS, with 6.25, 25 or 100 μM SLS or with 0.25, 1 or 10 nM DS toobtain a viral inoculum of 3×10⁵ PFU/50 μl. Mice were anesthetized byintraperitoneal injection of a mixture containing 70 mg/kg ketaminehydrochloride (Rogarsetic* injection USP; Rogar/STB Inc. Montreal, QC,Canada) and 11.5 mg/kg xylazine (Rompun®; Miles Canada Inc., Etobicoke,ON, Canada). The virus was inoculated on the lateral side of the body inthe left lumbar skin area. The skin was scratched six times in acrossed-hatched pattern with a 27-gauge needle held vertically. Viralsuspension (50 μl) was deposited onto the scarified area and rubbed for10 to 15 sec with a cotton tipped applicator saturated with EMEM+2% FBSor SLS or DS solutions. The scarified area was protected with a corncushion which was maintained on the mice body with surgical tape. Theporous inner wall of the aperture of the corn cushion wasimpermeabilized with tissue adhesive prior to use to prevent absorptionof the drug. The aperture of the corn cushion was also closed withsurgical tape. Mice were then returned to their cages and observed twicedaily.

FIG. 7 shows the time evolution of the mean lesion score of hairlessmice infected cutaneously with HSV-1 (strain F) pretreated withdifferent concentrations of SLS or DS for 1 h at 37° C. The evaluationof the lesion score was performed according to the criteria presented inTable 2. In infected untreated mice, no pathological signs of cutaneousinfection were visible during the first four days following infectionand only the scarified area remained appearent. On day 5, herpetic skinlesions began to appear in some mice in the form of small vesiclesdistant from the inoculation site. On day 6, almost all untreated micedeveloped herpetic skin lesions in the form of a 4-5 mm wide bandextending from the spine to the ventral midline of the infecteddermatome similar to zoster-like infections. Maximal mean lesion scorewas observed on day 8. Mean lesion score decreased thereafter from day11 to day 15 because of spontaneous regression of cutaneous lesions insome mice. Mice infected with the virus pretreated with 6.25 and 25 μMSLS did not demonstrate a significant reduction of the mean lesionscore. However, mice infected with the virus pretreated with 100 μM SLSdid not demonstrate any signs of cutaneous lesions. Of prime importance,all mice infected with the virus pretreated with 100 μM SLS survived theinfection (data not shown). On the other hand, mice infected with thevirus pretreated with 0.25 nM DS showed a partial reduction of the meanlesion score whereas mice infected with the virus pretreated with either1 or 10 nM DS gave better protection against the development of herpeticlesions.

TABLE 2 Criteria used for the evaluation of herpetic cutaneous lesionsScore Appearance of the lesion 0 No visible infection 1 Infectionvisible only at inoculation site, scarification area 2 Infection atinoculation site only, with swelling, crust and erythema 3 Infection atinoculation site with discrete lesions forming away from inoculationsite 4 Rash visible around half of body but not yet confluent 5 Rashconfluent but not yet necrotic or ulcerated 6 Complete rash withnecrosis or ulceration, hind limb paralysis, bloating, death

In Vivo Prophylactic Effect of Poloxamer Formulations Containing or notSLS (Cutaneous Model)

The efficacy of the poloxamer alone and of the poloxamer containing 5%SLS to prevent the development of cutaneous lesions in mice has alsobeen evaluated. Female hairless mice (5-6 weeks old) were usedthroughout this study. In brief, mice were anesthetized byintraperitoncal injection of a mixture containing 70 mg/kg ketaminehydrochloride and 11.5 mg/kg xylazine. The formulations were appliedtopically on the lateral side of the body in the left lumbar skin area.Five minutes and 1 hour after the application, one drop of viralinoculum (3.15×10⁸ PFU/ml) was deposited onto the skin and ascarification was made with a 27G needle throughout the drop to mimic anaccident that may occur to health care workers. In this model, the viralinoculum needs to be higher to obtain a complete zosteriform rash inalmost all mice. However, the mortality associated to infection was lowand could not be used as a criteria to evaluate the efficacy oftreatments. The scarified area was protected with a corn cushion whichwas maintained on the mice body with surgical tape. The aperture of thecorn cushion was also closed with surgical tape. Mice were then returnedto their cages and observed twice daily.

FIG. 8 shows the time evolution of the mean lesion score of infecteduntreated mice and of mice pretreated with the poloxamer alone orpoloxamer containing 5% SLS 5 min or 1 h prior to their cutaneousinfection with HSV-1 (strain F). Results show that mice pretreated withthe gel alone 5 min or 1 h prior to infection give only a modestprotection against the development of cutaneous lesions. Of primeinterest, in mice pretreated both 5 min or 1 h with the poloxamercontaining 5% SLS, a complete protection against the development ofcutaneous lesions was observed. These results show the great potentialof our formulations as a prophylactic approach to prevent infection withpathogens. Such a tool could indeed protect against accidental infectionof health care workers.

In Vivo Efficacy of Gel Formulations to Protect Against Infection Causedby Herpes Viruses (Intravaginal Model)

The efficacy of gel formulations to prevent the genital transmission ofHSV-2 has been evaluated in a murine intravaginal infection model. Inbrief, female Balb/c mice aged 4 weeks were used for this study. Toincrease susceptibility of mice to herpes, 2.5 mg of progesterone(Depo-Provera) was administered subcutaneously to each mouse 7 daysprior to and one day prior to inoculation with HSV-2. Anesthetized micewere inoculated with 5 μl of 2.4×10⁷ pfu/ml of HSV-2 (strain 333) afterswabbing the vagina with a calcium alginate thin tipped swab. Todetermine the efficacy of the gel formulations to block herpesinfection, 15 μl of the gel was delivered with a pipette tip into thevagina a few minutes prior to the inoculation. The pipctte tip was movedin and out four times to simulate stirring action of sexual intercoursewhile being cautious not to cause any bleeding.

FIG. 9 shows the mean lesion score and survival rate of infecteduntreated mice and of mice pretreated intravaginally with the gel aloneprior to infection with HSV-2 (strain 333). Four days post-infection,infected untreated animals demonstrated perineal oedema and redness andby 6 to 12 days, most of them died of encephalitis. Of prime importance,all mice pretreated with the gel alone survived the infection and didnot demonstrate any sign of illness up to 16 days post-infection. Thepresence of the gel alone could thus abolish HSV-2 infection.

FIG. 10 shows the survival rate of infected untreated mice and of micepretreated intravaginally with 2.5% SLS or gel containing 2.5% SLS priorto infection with HSV-2 (strain 333). Four days post-infection, infecteduntreated animals demonstrated perineal oedema and redness and by 6 to12 days, most of them died of encephalitis. Of prime importance, allmice pretreated with either 2.5% SLS alone or gel containing 2.5% SLSsurvived the infection and did not demonstrate any sign of illness up to16 days post-infection. Taken together, these results clearly indicatethat the use of our gel preparation could represent an innovativepreventive measure to reduce the sexual transmission of herpes, HIV andother pathogens causing STDs.

FIG. 11 shows the survival rate of infected untreated mice and of micepretreated intravaginally with gel containing various compounds prior toinfection with HSV-2 (strain 333). Those compounds were selected torepresent other sulfated and non-sulfated compounds having or notdetergent properties. They also represent various ionic (anionic andcationic) and non-ionic compounds. This screening approach was aimed tofind other potential candidate microbicides. Results showed that the gelformulation containing 2.5% lauroyl sarcosine gave complete protectionagainst infection (100% survival). On the other hand, the gelformulations containing 2.5% benzalkonium chloride, 5% polyoxyethylene40 stearate and 5% guanidine gave 60, 60 and 30% survival, respectively.Our preliminary results showed that lauroyl sarcosine has good potentialas a candidate microbicide that we are actually exploring now. However,other compounds such as benzalkonium chloride, polyoxyethylene 40stearate and guanidine that showed partial microbicidal potential canalso be explored by optimizing their concentration for better efficacy.Alternatively, combinations of these compounds may also provide optimalefficacy, if compatible. Without being bound to any theory, it isenvisageable that the combination of a detergent with a chaotropic agentmay provide for an efficacy as good as or even better than SLS. Theseare specific examples of potential microbicides, but are in no wayintended to limit the scope thereof.

Design of Applicator for Vaginal/ano-rectal Delivery of Formulations

As mentioned above, it is an object of the present invention to provideformulations to prevent infection and/or abnormal conditions of mucosaeand/or skin caused by any pathogen and/or any disease. For vaginalapplications, any topical formulations should be administered using anapplicator which allows uniform distribution of the content to theentire vagina (delivery to sides) and cervix (delivery to front) formaximal efficacy. Therefore, we have designed a unique applicator whichallows about 360° distribution of its content into the vagina and far tothe cervix which is a great improvement over existing conventionalvaginal applicators which deliver contents only to front (cervix area).The different objectives to achieve and the main characteristics thatour unique applicator should have to deliver topical formulationsinclude:

a) Uniform distribution of topical formulations as liquid or gel to theentire vagina/cervix

b) Efficient and rapid delivery of its content

c) Resistance to temperature variations (−40 to 60° C.)

d) Compatibility of the polymer of the applicator with the gelformulations

e) Ease of sterilization

f) No leakage

g) Ease of manipulation and insertion

h) Resistance to breakage, to expansion of content and to vibrations dueto transport

i) Compatibility with agents and/or conditions present in thesurrounding environment

Technical Background and Strategy

The efficacy of a formulation to block the sexual transmission ofpathogens causing STDs depends i) on the nature of the formulation to bedelivered and ii) on its ability to cover the entire vaginal/cervixarea. Unlike other products, we have a unique formulation withthermoreversible property which is delivered in liquid form assuring agood penetration of the formulation into the smallest irregularities ofthe vaginal/cervical mucosae. For maximum protection, such a formulationshould cover the entire vagina/cervix. However, the existingconventional vaginal applicators have a unique hole at the tip so thatthe content is delivered only to the cervix area excluding the vagina,limiting therefore its efficacy. Our unique vaginal applicator will havemultiple holes and/or slots (at the tip and on the sides) to deliver ourformulation or any other film-forming component, gel, cream, ointmentand/or antimicrobial, bactericidal, virucidal, chemotherapeutic,antiinflammatory, antineoplastic, or immunomodulatory agent, detergents,microbial adsorption inhibitor, skin penetration enhancing agent,cytokine, antigen, vaccines, or combination of them thereof to treat orprevent STDs, cancer or any other disease, to uniformly cover both thevagina and cervix for maximal protection. Literature searches revealedthat there is no applicators or similar products on the market havingsuch a design which allow delivery of their content to the entirevagina/cervix.

Characteristics of our Applicator

All of the existing vaginal applicators deliver formulations in a formof gel/cream which has the disadvantage of not covering the wholevagina/cervix area. On the other hand, our formulation has an importantthermoreversible property being liquid at room temperature and gelifyingat body temperature. When delivered as liquid, our formulation wouldcover the whole vagina/cervix and it would penetrate through thesmallest irregularities of vaginal and cervical mucosae. For our uniqueformulation or any other film-forming component, gel, cream, ointmentand/or antimicrobial, bactericidal, virucidal, chemotherapeutic,antiinflammatory, antineoplastic, or immunomodulatory agent, detergents,microbial adsorption inhibitor, skin penetration enhancing agent,cytokine, antigen, vaccines, or combination of them thereof to treat orprevent STDs, cancer or any other disease, we need a unique applicatorto deliver from the very end as well as sides to cover the wholevagina/cervix which is the key factor for offering maximal protectionagainst pathogens causing STDs. The major characteristics of theapplicator are discussed below (see also Table 3):

a) Uniform Distribution of Topical Formulations as Liquid or Gel to theEntire Vagina/cervix

The applicator must deliver the formulation uniformly and must cover thewhole vagina/cervix area by delivering through apical and lateral holes.Furthermore, the applicator should deliver sufficient amount to coverboth cervix and vagina. This will allow maximal protection ofindividuals against pathogens causing STDs.

b) Efficient and Rapid Delivery of its Content

Most existing vaginal applicators deliver only a fraction of its contentlimiting the efficacy of the formulation. Therefore, the applicator mustdeliver either all of its content without leaving residual material inthe reservoir or deliver the quantity required for sufficient coverageof all target mucosae. This will be achieved through the design of thereservoir and calculating the average force of the fingers pressing onit to release its content. The time of delivery will vary depending onwhether the content is delivered as a liquid, semi-viscous or gel.However, the delivery of applicator's content must be rapid.

c) Resistance to Temperature Variations (−40 to 60° C.)

The applicator must resist temperature variations because storage andtransport environments will vary greatly from one country to another. Itshould be designed so that the applicator and the formulation remainunchanged under temperature conditions ranging from −40 to 60° C.

d) Compatibility of the Polymer of the Applicator with the Gel

The polymer used for the development of the vaginal applicator shouldnot affect the properties of the gel formulation (stability, viscosityparameters, non-cytotoxicity, efficacy to block pathogens, etc.).

e) Ease of Serilization

The applicator design and material must ensure that it can be sterilizedusing a suitable method and should not result in changes in thecharacteristics of it or its content.

f) No Leakage

The applicator must be leak-proof under storage and transportconditions. If boxes are stacked on top of each other, the applicatorshould not leak its content.

g) Ease of Manipulation and Insertion

The applicator must be user friendly, easy to manipulate and easy toinsert without causing any discomfort to its user. Furthermore, itshould be appealing to users.

h) Resistance to Breakage, to Expansion of Content and Vibrations Due toTransport

The applicator should resist breakage if it falls from the user's handor when it is handled during transport. It should also resist expansionof its content. Furthermore, the applicator should be stable and resistto vibrations during transport.

i) Compatibility with Agents and/or Conditions Present in theSurrounding Environment

The applicator should resist to the agents and/or various conditionspresent in the surrounding environment. For example, it should not beaffected by vaginal acidic pH, vaginal discharges or other similarconditions.

TABLE 3 Desired functions and target values of the applicator NoFunction Description Target value 1 Distributes formulation as Onceintroduced, proceed to Quantity about 3-5 ml liquid, semi-viscous, gel,expulsion and distribution of cream, ointment or any formulationfilm-forming component 2 Distributes formulation Distributes formulationto Distributes over about uniformly cover the whole vagina/cervix 3600in vagina and over about 3600 in cervix 3 Contains formulation asApplicator has reservoir Minimal content of liquid, semi-viscous, gel,injected volume cream, ointment or any film-forming component 4Leak-proof No leakage from package and 0 ml after initial manipulation 5Easy to manipulate Applicator can be held easily Favourable opinion ofand is user friendly volunteers (7/10) 6 Easy to insert Applicatorinserted without Average diameter of pain and minimal resistance about0.5 inch (12.5 mm) 7 Delivers to vagina/cervix The applicator lengthallows it Average length of to reach cervix about 4.5 inch (115 mm)including reser- voir and holding 8 Resists to fall The applicatorshould not Fall of about 60 inch break and content should not (1.5 m)leak if it falls from user's hands 9 Resists to surrounding Theapplicator should not be Data from manufacture environmental conditionsaffected by its content, of thermoplastic resin vaginal secretions orpackaging material 10 Not toxic and does not Does not affect the Datafrom manufacture affect surrounding envi- composition or quality of ofthermoplastic resin ronmental conditions formulation; it should also notand topical formulation affect the surrounding envi- owner ronment 11Resists to vibration dur- The applicator and reservoir Standards to beverified ing transport should not be damaged and should operate normallyafter transport 12 Be efficient Be operational (delivers Favourableopinion of content and distributes evenly volunteers (9/10) withoutfailure) 13 Delivers fast Content is rapidly ejected About 5 sec fromapplicator 14 Resists to temperature The applicator should not be −40°C. to +60° C. variation affected by temperature variations 15 Can berinsed under Can be rinsed if drops from Data from manufacture wateruser's hands of thermoplastic resin 16 Sterilizable Suitable method tobe selected Standards to be verified

The following are examples of some different concepts which are intendedto describe some of the general design possibilities of the applicator,but are in no way intended to limit the scope thereof. It is importantto mention that the final shape of the applicator can differ from theexamples given herein. It is deemed that such designs can be modified tosuit anorectal application.

FIGS. 12-15 illustrate specific examples of applicators according to anaspect of the present invention. The following disclosure describes fourembodiments of applicators illustrated in these figures.

Generally stated, the present applicator is designed to uniformlydeliver any formulation as liquid, semi-viscous, gel, cream, ointment orany other film-forming component described herein above into a mucosalcavity, with the smallest residual amount thereof left within theapplicator. The present applicator comprises a longitudinally extendingbody which has proximal and distal ends. The proximal end is locatedclose to the external site of the mucosal cavity accessible to thepatient. The body has external perforations, made as a series of slotsor holes, for uniform distribution of any formulation as described aboveto be delivered to the patient's mucosal cavity. Upon insertion of theapplicator and expulsion of the formulation in the mucosal cavity, theformulation which is contained in a reservoir, should advantageouslytravel through a diffusion channel having a small volume, prior to beingexpelled through the perforations. Indeed, this allows both the rapidexpulsion of the formulation and the minimization of the quantity offormulation left in the applicator after expulsion.

The diffusion channel is created by a free space between two wallsdefining the body. The first wall is an external wall of the body andincludes apertures. The second, non perforated, internal wall isprovided inside the first wall to create the diffusion channel. Theinternal wall is so configured and sized that it can be slidablyinserted into the first wall. Alternatively, the internal wall, sized tobe smaller than the first one, may be integrally molded with theexternal wall of the body.

The internal wall has a proximal end which is an inlet end for theformulation into the diffusion channel. A directing element may also beprovided to direct the formulation into the inlet end of the diffusionchannel. The directing element therefore prevents entry of theformulation into another compartment than the diffusion channel.

A reservoir capable of receiving the formulation is also part of theapplicator. The reservoir can be located near the body of the applicatoror inside the body. The reservoir is operatively connected to anexpulsion element. The expulsion element is itself connected to theproximal end of the body through a connector element. The expulsionelement is actuated by the patient. Upon application of compression,pull or push movements, the expulsion element releases the content ofthe reservoir, which is contacted with the proximal entry end of thediffusion channel. The formulation therefore travels into the diffusionchannel to the mucosal cavity, being expulsed through the perforations.

Turning now to FIGS. 12a-12 d of the appended drawings, a firstembodiment of an applicator according to an aspect of the presentinvention will be described. FIG. 12b shows an exploded view of thisfirst applicator. The external wall (1) of the body of the applicatorshows perforations (2) (only one shown) made as one single slotextending from one side of the body through the opposite side with nointerruption at the distal end of the external wall (1). Thelongitudinal slot therefore defines lateral and distal perforations. Inthis embodiment, the reservoir and the expulsion element are one singleelement (3) made of a compressible material. The formulation iscontained in the reservoir which ejects its content by pressing it withfingers. The reservoir is terminated by a membrane of low resistance tocompression (4). The reservoir being the expulsion element, it isconnected to the proximal end of the body through a connector element(5) represented by a screwable or snap-in connector element. In thisparticular embodiment, the internal wall (6) of the body is provided asa separated element dimensioned to be smaller than the external wall.The proximal end of the internal wall terminates with a protrudingcollar that sits onto the connector element formed at the proximal endof the external wall. The proximal part of the internal wall comprises aclosing element (7) which closes the internal lumen formed by theinternal wall. The closing element may have the shape of a disc.Alternatively, the proximal end of the internal wall may be integrallymolded with the latter to be simply closed. Concentric to this closingelement, there is an open concentric element (8) located at theperiphery of the closing element. These elements provide for a generallycalled directing element, which directs the formulation into thediffusion channel formed between the internal and the external walls andaway from the internal surface of the internal wall (6). FIG. 12c alsoshows a tapered element (9), located at the centre of the directingmeans, provided to break the membrane (4) when adequate pressure isapplied.

A second embodiment of the applicator is illustrated in FIG. 13. Thesame peripheral and internal walls as in FIG. 12 are used in thisapplicator. However, a plurality of slots regularly spaced from eachother are provided in the external wall. In this specific version, theexpulsion element and the reservoir are also one single element.However, the expulsion element is not a compressible reservoir. It israther a piston-like structure (10) which comprises the formulationprovided in a pouch (11). In this embodiment, the connector element (5)is telescopically insertable in the piston-like structure (10). Thepouch is made of a material of low resistance to compression. To breakthis membrane, a tapered element is provided at the proximal end of theinternal wall. FIG. 13 shows this tapered element (9) as a disc providedwith a pointed portion. The disc sits on the proximal end of theinternal wall, the pointed portion facing the pouch (11). In use, thepiston-like structure (10) is pressed by the user, the membrane is thuspierced by the pointed portion, and the formulation is thus forcedthrough the diffusion channel, and expelled through the perforations.

FIG. 14 illustrates a third embodiment of the present applicator. Whilethe two previous embodiments show a reservoir located near the proximalend of the diffusion channel, this third embodiment shows a reservoir(12) provided away from the proximal end of the diffusion channel. Inthis: case, a seat (13) located away from the reservoir is provided. Theseat is operatively connected to the piston (14) located proximally tothe reservoir (12). The user pulls the piston and therefore compressesthe reservoir, the content of which is engaged into the proximal inletend of the diffusion channel. The formulation is expulsed throughperforations made in the external wall of the body of the applicator,shown in FIG. 14 as a plurality of holes (2). The holes are spaced insuch a way that the formulation is uniformly distributed into themucosal cavity. The holes are located in the longitudinal section of theexternal wall as well as to the distal end thereof. FIG. 14 furthershows that the internal and external walls of the body of the applicatormay be integrally formed. Alternatively, the internal wall may also takethe shape of the one shown in FIGS. 12 and 13, without the need of atapered element. The reservoir may include a membrane of low resistanceto compression in such a way that, when compressed by the pull movementof the piston (14), the membrane breaks and discharges its content intothe diffusion channel. In this embodiment of the applicator, thedirecting element is formed by the proximal entry end of the diffusionchannel and a closing element located this time at the proximal end ofthe body (not shown).

FIG. 15 shows a fourth embodiment of the applicator according to anaspect of the present invention. In this embodiment, the reservoir andexpulsion element are a single element. A membrane (4) of low resistanceis located close to the proximal end of the body (1). The external wallof the applicator comprises slots that are practised as a plurality ofgrooves. The internal wall (6) is integrally formed with the outer wall.The internal wall terminates at its proximal end with a tapered element(15). The reservoir/piston (16) has a diameter which is slightly largerthan the external diameter of the internal wall, but smaller than theinternal diameter of the external wall of the body of the applicator. Inuse, the reservoir is slidably engaged between the two walls, themembrane is pierced and its contents are forced in to the diffusionchannel and in the perforations located on the sides and at the distalend of the external wall.

It is to be noted that in all the above described embodiments, thedirecting element may be integrally formed with the proximal end of theinternal wall of the body or be provided as a closing element or disc toblock the passage of the formulation into the internal lumen formed bythe internal wall and to direct the flow of the formulation into thediffusion channel.

Further, for ease of use, grasping elements may be provided in someembodiments to help the user maintain the applicator in place whileactuating the expulsion element. More specifically, in the secondembodiment, the grasping element is defined by the annular collar (17)formed at the outer periphery of the connector element (5). The annularcollar has an external thickness such that the user has enough space tograsp the distal end of the collar between fingers and push the pistonwith another finger. In the third embodiment, the grasping element isprovided at the proximal end of the piston (see numeral 18). Theexternal wall of the body being of a larger section than the piston, theuser can hold the body of the applicator by its proximal end with onehand and pull the piston with another. Finally, in the fourthembodiment, the grasping element is provided as an elliptic handle (19)located at the proximal end of the body of the applicator andsurrounding the connector element. This handle may be held between twofingers, while the piston is pushed with another finger.

Examples Involving our Poloxamer Formulations for Treatment of Infection

For the purpose of testing the efficacy of our gel formulations in amurine model of cutaneous HSV-1 infection, the solutions were preparedwithin a phosphate buffer (0.2 M, pH 6) to be compatible with the pH ofthe skin.

Comparative Efficacy of Topical Formulations of Foscarnet, Acyclovir,and of Zovirax Ointment Against HSV-1 Cutaneous Lesions in Mice

The efficacy of our different topical formulations has been evaluated ina murine model of cutaneous HSV-1 infection. In brief, female hairlessmice (SKH1; Charles River Breeding Laboratories Inc., St-Constant, QC,Canada), 5-7 weeks old were anesthetized by intraperitoneal injection ofa mixture containing 70 mg/kg ketamine hydrochloride and 11.5 mg/kgxylazine. The virus was inoculated on the lateral side of the body inthe left lumbar skin area. The skin was scratched six times with a 27gauge needle held vertically in a crossed-hatched pattern. Fifty μl ofviral suspension (HSV-1 strain F, 1.5×10⁶ plaque forming units (PFU)/ml)was rubbed for 10 to 15 sec on the scarified skin area with a cottontipped applicator saturated with culture medium [minimum essentialmedium (MEM) supplemented with 100 U/ml of penicillin-streptomycin, 2 mML-glutamine and 2% fetal bovine serum (MEM-E+2% FBS)]. The scarifiedarea was protected with a corn cushion which was maintained on the micebody with surgical tape. The porous inner wall of the aperture of thecorn cushion was impermeabilized with tissue adhesive prior to use toprevent absorption of the drug. The aperture of the corn cushion wasalso closed with surgical tape. Mice were then returned to their cagesand observed twice daily.

Different treatment regimens were evaluated in this study. Briefly, thetape closing the aperture of the corn cushion was removed and thescarified area was cleaned with a cotton tipped applicator saturatedwith cold water. Fifteen μl of the different formulations was appliedonto the scarified area. The aperture of the corn cushion was closedwith surgical tape to avoid rapid removal of the drug by the mice. Thisprocedure also prevents accidental systemic treatment that could occurdue to potential licking of the treated lesions. The efficacy of thedifferent formulations was evaluated using lesion scores and survival.

FIG. 16 (Panel A) shows the time evolution of mean lesion score ofinfected untreated mice or mice treated with foscarnet in solution orincorporated into poloxamer. Treatment was started 24 h after infectionand was repeated 3 times daily for 4 days. In mice treated with thepoloxamer alone, we observed a pattern largely similar to that seen withuntreated mice except that the regression of cutaneous lesions seemed togo faster in the latter group. In mice treated with a solution of 0.5%foscarnet, we observed a large reduction of mean lesion score which wasmore pronounced when the drug was associated to the poloxamerformulation. FIG. 16 (Panel B) shows the corresponding survival forinfected untreated mice and mice treated with the drug formulations.Death by encephalitis occured in 75% of untreated infected mice betweenday 7 and day 8. The mortality was similar in mice receiving thepoloxamer alone and occured between day 8 and 10. Half of the micetreated with foscarnet in solution survived the infection. Of primeinterest, 75% of mice treated with the poloxamer formulation offoscarnet survived the infection (p<0.05).

FIG. 17 (Panel A) shows the time evolution of the mean lesion score ofinfected untreated mice and of mice treated with a single application at24 h post-infection of the poloxamer containing 5% acyclovir or theZovirax® ointment. Of prime interest, the poloxamer formulationcontaining 5% acyclovir demonstrated a good efficacy against thedevelopment of cutaneous lesions in mice, whereas the Zovirax® ointmentexerted only a modest effect. However, acyclovir incorporated into thepoloxamer significantly reduced the lethality (p<0.05), but not theZovirax® ointment (Panel B). The higher efficacy of the poloxamerformulation of acyclovir over the commercial Zovirax® ointment highlysuggests that the poloxamer could be a better vehicle for the topicaldelivery of this drug.

FIG. 18 (Panel A) shows the time evolution of the mean lesion score ofcontrol mice and of mice treated 3 times daily during 4 days andinitiated 5 days post-infection with the poloxamer alone, poloxamercontaining 5% acyclovir or the Zovirax® ointment. In mice receiving thepoloxamer alone, a reduction in the mean lesion score compared toinfected untreated mice was observed. Treatment with the Zovirax®ointment exerted only a modest effect. However, a marked reduction ofthe mean lesion score was observed for mice treated with the poloxamerformulation containing 5% acyclovir when compared to untreated infectedanimals. Of prime interest, all mice treated with the poloxamercontaining 5% acyclovir survived the infection (p<0.001) (FIG. 18, PanelB). Treatment with Zovirax® ointment increase to a lesser extent thesurvival of infected mice (p<0.05).

In Vivo Skin Penetration of Antivirals

FIG. 19 shows the distribution of foscarnet and acyclovir in skintissues of uninfected (Panels A, C, E) and infected (Panels B, D, F)mice at 24 h after their topical application, either in phosphate bufferor in the poloxamer matrix. The distribution of both formulations offoscarnet and of the buffered solution of acyclovir was similar in thestratum corneum tape strips of uninfected and infected mice. Incontrast, the incorporation of acyclovir into the poloxamer markedlyincreased the amount of drug recovered in the stratum corneum of bothuninfected and infected mice; the increased drug penetration being morepronounced in infected mice. No or negligible amounts of foscarnet werefound in the underlying epidermis and dermis of uninfected miceirrespective of the carrier used for the drug application. Theconcentration of foscarnet in the epidermis and dermis of infected micewas significantly higher when the drug was incorporated within thepoloxamer. The concentration of acyclovir was higher than that offoscarnet in the epidermis and dermis of both uninfected and infectedmice irrespective of theicarrier used. The concentration of acyclovirincorporated within the poloxamer in the epidermis of uninfected micewas 6.1-fold greater than that of the drug in the buffered solution.Infection of mice did not significantly increase the amount of acyclovirin the epidermis. The concentration of acyclovir in the dermis ofinfected mice was 7.9-fold greater than that in uninfected mice when thedrug was administered in the poloxamer matrix.

FIG. 20 shows the concentration of acyclovir in plasma of uninfected andinfected mice at 24 h after its topical application, either in phosphatebuffer or in the poloxamer matrix. Similar concentrations of acyclovirwere found in plasma of uninfected mice for both formulations. Infectionof mice markedly increased the concentration of acyclovir in plasma,especially when the drug was incorporated within the poloxamer matrixfor which a 4-fold increased concentration was reached. Theconcentration of acyclovir in the plasma of infected mice was 2.1 foldgreater when the drug was incorporated into the poloxamer matrix.

Effect of SLS on the Efficacy of Poloxamer Formulations ContainingFoscarnet or Acyclovir Against HSV-1 Cutaneous Lesions in Mice

The influence of SLS on the efficacy of poloxamer formulationscontaining foscarnet against HSV-1 infection has also been evaluated inmice. FIG. 21 (Panel A) shows the time evolution of the mean lesionscore of untreated infected mice and of infected mice treated with asingle application (given 24 h after the infection) of the poloxameralone, poloxamer containing 3% foscarnet, poloxamer containing 5% SLS,or poloxamer containing 3% foscarnet+5% SLS. Poloxamer alone did notgive any protection against infection. Furthermore, a modest decrease inthe mean lesion score was observed in mice treated with poloxamercontaining either 5% SLS or 3% foscarnet when compared to untreatedinfected mice. Of prime interest, in mice treated with the poloxamercontaining 3% foscarnet and 5% SLS, we observed a marked and significantreduction (p<0.05) in the mean lesion score compared to that ofuntreated infected mice. The corresponding survival rates for the sametreatment groups are given in Panel B which support the results of meanlesion scores. The skin penetration enhancer property of SLS combinedwith its ability to modify viral infectivity could explain the enhancedefficacy of the foscarnet formulation.

In Vitro Susceptibility of HSV-1 to Combination of Foscarnet and SLS

The effect of SLS on the efficacy of foscarnet against HSV-1 (strain F)was investigated in Vero cells. In brief, cells were seeded in 24well-plates (Costar, Montreal, QC, Canada) and were incubated with HSV-1strain F (approximately 100 PFU/ml) for 2 h at 37° C. to allow virusadsorption. Afterwards, virus was removed and cells overlaid with 0.5 mlof 0.6% agarose Seaplaque (Marine Colloids, Rockland, Mass.) containingdifferent concentrations of foscarnet, SLS or combination of bothcompounds. The plates were incubated for 2 days at 37° C. Cells werethen fixed with 10% formaldehyde in PBS for 20 min, washed withdeionized water and stained with 0.05% methylene blue. Virussusceptibility was evaluated via the determination of PFU. FIG. 22 showsthe susceptibility of HSV-1 strain F to combination of differentconcentrations of foscarnet and SLS on Vero cells. Results show that thepresence of SLS enhanced the efficacy of foscarnet against HSV-1 (strainF) in Vero cells.

Potential Applications

The following examples described herein below are specific potentialapplications of our topical formulations, but are in no way intended tolimit the scope thereof. As demonstrated in the above results, our gelformulations could be used for the prevention of infection of skinand/or mucosae and more particularly for the prevention of HSV and HIV.In addition, our results showed that our gel formulations can serve as aprophylactic agent to prevent accidental infection of health careworkers. As also demonstrated in the above results, our gel formulationscould be used for the treatment and prevention of infection ofconditions of skin and/or mucosae and more particularly for thetreatment and prevention of herpetic lesions. Beside the aboveapplications, further potential applications are to use our gelformulations i) for the healing and/or treatment of burn wounds andprevention of further infection and ii) for the treatment and/orprevention of infection of ophthalmic conditions. In the above examples,our gel formulations may contain any antimicrobial, bactericidal,virucidal, chemotherapeutic, antiinflammatory, antineoplastic,immunomodulator or any other agent or combination of them which iseffective for the treatment and/or prevention of infection and/orabnormal conditions of mucosae and/or skin caused by any pathogen and/orany disease.

The following examples described herein below are specific potentialuses of our unique applicator, but are in no way intended to limit thescope thereof. As described above, our applicator could be used for thedelivery of any topical formulations used to covercervical/vaginal/ano-rectal mucosae for the treatment and/or preventionof infection and/or abnormal conditions of mucosae. Our applicator couldalso be used to deliver i) any topical formulations that can prevent thesexual transmission of pathogens causing STDs, ii) vaginal contraceptiveformulations, iii) topical microbicidal formulations against specificdiseases and iv) any antimicrobial, bactericidal, virucidal,chemotherapeutic, antiinflammatory, antineoplastic, or immunomodulatoryagent, detergents, microbial adsorption inhibitor, skin penetrationenhancing agent, cytokine, antigen, vaccines, radioactive agents orcombination of them thereof.

What is claimed is:
 1. A barrier-forming composition consistingessentially of a poloxamer, a buffer solution and an effective amount ofan agent capable of disrupting membrane or protein conformation in atarget cell, tissue or mucosa, whereby, when applied to the surface of aperson's skin or mucosa, the composition forms a protective semi-solidlayer on the skin or mucosa, effective to provide a physical barrier anda chemical barrier against a pathogen, With the proviso that said agentis neither nonoxynol-9, benzalkonium chloride nor menfegol.
 2. Abarrier-forming composition as defined in claim 1, wherein said agentincludes a chaotropic component in an amount sufficient to enhance thedisrupting effect towards said pathogen.
 3. A barrier-formingcomposition as defined in claim 1, wherein said agent comprises lauroylsarcosine or polyoxyethylene 40 stearate.
 4. A barrier-formingcomposition as defined in claim 1, wherein said agent comprises sodiumlauryl sulfate or guanidine.
 5. A barrier-forming composition as definedin claim 1, wherein said poloxamer is poloxamer
 407. 6. Abarrier-forming composition as defined in claim 5, wherein saidpoloxamer 407 is present in a concentration of about 5%-50% (w/w).
 7. Abarrier-forming composition as defined in claim 5, wherein saidpoloxamer 407 is present in a concentration of about 15%-35% (w/w).